Trigger mechanism

ABSTRACT

A trigger mechanism for a semiautomatic firearm having a reciprocating bolt assembly, the mechanism having a trigger member which is releasably connected to a sear member. The trigger member is disconnected from the sear by reciprocation of the bolt assembly or by actuation of a safety. Means are provided for adjusting the trigger pull and for retaining the preset trigger pull against maladjustment.

United States Patent [72] Inventors William J. Billett Fairrnont, Minn.;Edwin S. Vartanian, North Haven, Conn. [21 1 Appl. No. 793,958 [22]Filed Jan. 27, 1969 [45] Patented May 4, 1 971 [73] Assignee OlinMatltieson Chemical Corporation [54] TRIGGER MECHANISM l 1 Claims, 7Drawing Figs.

[52] US. Cl 89/145, 89/148 [51] Int. Cl F4lc 19/00 [50] Field of Search42/69 (A,B);89/l40l50 [56] References Cited UNITED STATES PATENTS1,997,954 4/1935 VonFrommer 42/698 Primary Examiner--Benjamin A.Borchelt Assistant Examiner-Stephen C. Bentley Attorneys-H. SamuelKieser, Donald R. Motsko, William W. Jones, Richard S. Strickler, RobertH. Bachman, Donald R. Motsko and Thomas P. ODay ABSTRACT: A triggermechanism for a semiautomatic" firearm having a reciprocating boltassembly, the mechanism having a trigger member which is releasablyconnected to a sear member. The trigger member is disconnected from thesear by reciprocation of the bolt assembly or by actuation of a safety.Means are provided for adjusting the trigger pull and for retaining thepreset trigger pull against maladjustment.

4 Sheets-Sheet 1 INVENTORSI EDWIN $.VART4NIAN WILLIAM J. BILLET BY WM00.2w

ATTORNEY Patented May 4, 1971 4 Sheets-Sheet 2 INVENTORS' EDWIN S.VARTAN/AN WILLIAM J. BILLET BY 404;...- M),

ATTORNEY Patente d May 4, 1971 3,577,827

4 Sheets-Sheet ,5

ATTORNEY TRIGGER MECHANISM This invention relates to a trigger mechanismfor use with a bolt action, semiautomatic firearm, wherein the triggeris only connected to the sear when the bolt is locked in its batteryposition. When the bolt is moved out of its battery position, and towardits retired position, the trigger is automatically disconnected from thesear. The trigger is then free to more independently of the sear.

In bolt action, semiautomatic, self-loading firearms, a reliablemechanism is needed for disconnecting the trigger from the sear afterthe weapon is fired in order to allow the sear to reengage the hammerand prevent full automatic firing from accidentally occuring. Not onlyis it advantageous to disconnect the trigger from the sear after theweapon has been fired, it is also desireable that the trigger remaindisconnected from the sear until the bolt is locked in its batteryposition. This eliminates the chance that the weapon can be firedaccidentally while the bolt is not locked in its battery position, andthis also eliminates the disconcerting occurrence of having the hammerfall by pulling the trigger when the bolt is unlocked even though othersafety features prevent the weapon from firing in this condition.

It is also desirable, when firing a semiautomatic weapon, to eliminatepreliminary trigger take up which occurs before the gun is fired. Thephrase preliminary trigger takeup" refers to the initial movement of thetrigger which occurs when the latter is pulled, and which initialmovement does not result in disengagement of the sear from the hammer.This trigger take up impairs the accuracy of the shooter since itresults in a delay between aiming and firing, during which delay theaiming of the gun must be maintained steadily. By eliminating triggertakeup, pressure exerted on the trigger is immediately utilized todisengage the sear from the hammer.

The mechanism of this invention includes a trigger which is connected toa hammer sear when the bolt assembly is locked in its battery position,but which is disconnected from the hammer sear when the bolt is in itsreciprocation cycle. The trigger is formed in a unitary piece which ispivotally mounted for, and biased into, engagement with a connectorelement. The connector is movable into and out of contact with thehammer sear, so that when the connector contacts the sear, movement ofthe trigger is transferred to the sear through the connector. Adisconnector member is arranged for contact with the connector; thedisconnector being capable of moving the connector out of engagementwith the sear. This latter operation is accomplished duringreciprocation of the bolt assembly.

The mechanism of this invention also includes safety means which areoperable to prevent firing of the weapon when the bolt is locked in itsbattery position and the hammer is cocked. The safety performs the dualfunction of positively locking the sear into engagement with the hammer,and also moving the connector out of engagement with the sear. Thus,when the safety is on, the trigger is disconnected from the sear so thataccidental pulling of the trigger will not apply force to the sear andthe sear is locked against the hammer so that even jostling of the gunwill not result in an accidental firing.

Adjustment of the trigger pull force necessary to disengage the searfrom the hammer is accomplished by means of an adjustment screw whichbears against a spring which, in turn, bears against the sear.Adjustment of the screw varies the spring force directed against thesear resulting in a varying of the force with which the sear is movedagainst the hammer. When the trigger housing is mounted in the firearmreceiver, the adjustment screw is held against rotation by positiveengagement with the receiver so that the preadjusted trigger pull forcewill not vary as the gun is fired.

It is, therefore, an object of this invention to provide a triggerassembly for use with a semiautomatic, bolt-actuated firearm, whereinthe trigger can be connected to a hammer sear only when the bolt islocked in its battery position.

It is a further object of this invention to provide a trigger assemblyof the character described having a connector element movable into andout of engagement with the sear.

It is yet another object of this invention to provide a trigger assemblyof the character described wherein the trigger is biased at all timesinto engagement with the connector.

It is still another object of this invention to provide a triggerassembly of the character described having a disconnector memberoperable to move the connector out of engagement with the sear when thebolt is reciprocated.

It is a further object of this invention to provide a trigger assemblyof the character described having a safety actuable to disengage theconnector from the sear.

It is a further objective of this invention to provide a triggersearassembly which moves as a solid unit with no relative motion between thetrigger, connector or sear during the trigger pull cycle and thus givingthe sensation of crispness" to the shooter.

These and other objects and advantages of this invention will becomemore readily apparent from the following detailed description andaccompanying drawings, in which:

FIG. 1 is an exploded view of a preferred embodiment of the triggerassembly of this invention;

FIG. 2 is a side sectional view showing the trigger assembly of FIG. Imounted in a trigger housing and position in a firearm receiver, thevarious components being shown as they appear when the bolt is locked inits battery position, the hammer is cocked and the safety is off;

FIG. 3 is a fragmentary sectional view taken along line 3-3 of FIG. 2showing the manner in which the trigger pull adjustment is locked inplace in the receiver;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 2 with variousparts omitted for clarity, and showing the position of the safety whenthe latter is off;

FIG. 5 is a sectional view similar to FIG. 2, but showing the manner inwhich the connector is disengaged from the sear when the bolt isreciprocated; FIG. 6 is a sectional view similar to FIG. 2, but showingthe manner in which the safety is operable to disengage the connectorfrom the sear, while at the same time lock the sear into engagement withthe hammer; and

FIG. 7 is a sectional view taken along line 7-7 of FIG. 6 with certainparts removed for purposes of clarity.

Referring now to FIG. I, the various components of a preferredembodiment of the trigger assembly of this invention are shown. Theassembly includes a unitary trigger member 2 having an aperture 4 toreceive a trigger pin 6. The trigger 2 includes a laterally extendingflange 8 and a laterally extending lug 10. A connector 12 is disposedadjacent the trigger 2, the connector 12 being formed with a lip 14 anda downwardly extending projection 16. An elongated slot 18 is formed onthe connector 12 to receive the trigger pin 6, and the terminal portionof the connector is bent laterally at 20 for reasons more clearly setforth hereinafter. The connector 12 also includes a downwardly dependentprotrusion 22 which engages one end of a compressible spring 24. Theother end of the spring 24 engages the trigger flange 8.

A disconnector 26 is disposed adjacent to the connector 12, thedisconnector 26 including a forward elongated portion 28 and a rearwardelongated portion 30. The rearward elongated portion 30 includes a slot32 to receive the trigger pin 6, and the terminal 34 of the portion 30is disposed for engagement with the laterally bent portion 20 of theconnector 12. The medial portion of the disconnector 26 includes anelongated slot 36 which receives a hammer pin 38. A hammer 40 is biasedby a spring 42 for pivotal movement about the pin 38. The hammer 40includes a sear-engaging shoulder 44.

A sear 46 is pivotally mounted on the trigger pin 6, the sear 46including an aperture 52 through which an adjustment screw 54 extends.The screw 54 includes a radially enlarged head 56 having a fluted edgedefining alternating ridges 58 and valleys 60. A compressible spring 62is mounted on the screw 54 to bear against the rearward portion 50 ofthe sear 46 on one hand, and the screw head 56 on the other hand, whenthe screw 54 is mounted, the spring 62 serves to bias the sear 46 aboutthe pin 6, as will be explained in more detail hereinafter.

A safety 64 is positioned below the sear 46 and the connector 12 and isoperative to lock the trigger mechanism against firing, as will bedescribed in greater detail hereinafter. The safety 64 includes a recess66 having a cam surface 68 on one side thereof. A detent 70 biased by aspring 72 is disposed below the safety 64 and operates to keep thelatter is a preset position, e.g. either on or off.

Referring now to FIG. 2, the trigger mechanism is shown mounted in atrigger housing 74, which in turn is mounted in a firearm receiver 76. Apin 78 and a screw 80 serve to retain the trigger housing 74 in thereceiver 76. A bolt assembly 82, including a pair of slide arms 84, ismounted in the receiver, the bolt assembly 82 being shown in FIG. 2 inits battery position. The hammer 40 is shown in its cocked position withthe hammer spring 42 serving to bias the hammer 40 in a counterclockwisedirection about the pin 38. The lateral portion 48 of the sear 46engages the hammer shoulder 44 to retain the hammer 40 in its cockedposition.

The safety 64 is shown in its off position wherein the con nectorprojection 16 extends into the safety recess 66. The detent 70 ismounted in a well 86 which also contains the detent spring 72. Thedetent 70 is urged upwardly into a first concavity 88 is the bottom ofthe safety 64 to hold the latter in its off position.

The connector lip 14 engages the rear edge of the lateral portion 48 ofthe sear, the lip 14 being urged into this position by the spring 24.The trigger lug I is in contact with the top edge of the connector 12,the lug being urged into this position also by the spring 24. Thus thespring 24 serves to continuously urge the trigger 2 against theconnector 12 so that when the trigger is pulled, the motion imparted tothe trigger is immediately transferred to the connector, therebyeliminating preliminary trigger takeup. As previously noted, the spring24 serves to urge the connector 12 forwardly and downwardly, thus thelateral bend 20 of the connector is urged against the rear terminal 34of the disconnector 26. The forward elongated portion 28 is thus urgedforwardly to a position immediately behind the bolt slide arms 84. It isnoted that the elongated slots 32 and 36 in the disconnector 26 permitthe latter to slide back and forth over the pins 6 and 38.

The adjustment screw 54 is threaded into the rearward portion of thetrigger housing 74, with the spring 62 being sandwiched between thescrew head 56 and the rearward portion 50 of the sear 46. It is thusapparent that rotational changes in the position of the screw 54 willvary the quantum of force directed against the sear portion 50 by thespring 62, and thus the trigger pull force necessary to disengage thesear from the hammer 40 can be varied. A rib 90 projects from the rearface of the receiver 76 and engages one of the valleys 60 formed on thescrew head 56 when the trigger housing 74 is inserted into the receiver76. The screw 54 is thus held in place against rotation so as tostabilize the preset trigger pull force. FIG. 3 shows the placement ofthe rib 90 in one of the valleys 60 and best illustrates how theadjustment screw 54 is locked in place.

FIG. 4 shows the off position of the safety 64, it being noted that, inthis position, the connector 12 and the lateral portion 48 of the sear46 are both disposed over the safety recess 66, thus the connector 12and sear 46 can both be pivoted downwardly without interference from thesafety when the latter is off. It is noted that the detent 70 acts onthe first concavity 88 to hold the safety in its off position. Thesafety 64 also includes a second concavity 92 which cooperates with thedetent to hold the safety in its on position, as will be seen moreclearly hereinafter.

It is readily apparent from FIGS. 2 and 4, that when the trigger 2 ispulled in a counterclockwise direction, the trigger lug 10 will pivotthe connector 12 and the sear 46 in a counterclockwise direction aboutthe pin 6, thus disengaging the sear portion 48 from the hammer 40. Thehammer 40 then pivots about the pin 38 and fires the gun. A gas-operatedbolt-actuating system (not shown) of conventional design then causes thebolt assembly to reciprocate from its battery position to its retiredposition and return in a known manner.

FIG. 5 shows the position of the various elements of the triggerassembly when the bolt assembly 82 has moved rearwardly from its batteryposition during the reciprocation cy cle. As the bolt assembly 82 movesrearward, the slide arm 84 moves against the forward elongated portion28 of the disconnector 26 and causes the latter to slide rearwardly overthe pin 6 and 38. The slide arm 84 overrides the disconnector portion 28as the latter moves down a camming surface 94 in the receiver 76. Thusthe disconnector 26 remains in its rearward position, shown in FIG. 5,during substantially the entire reciprocation cycle of the boltassembly. As the disconnector 26 is moved to the rear, the rear terminal34 thereof moves against the laterally bent portion 20 of the connector12 sliding the latter rearwardly over the pin 6. The connector lip 14 isthus moved out of contact with the sear portion 48 so that the sear 46is free to pivot independently of the trigger 2 and connector 12. Thusas the hammer 40 is cocked by the rearwardly moving bolt assembly 82,the sear portion 48 is biased upwardly by the spring 62 so that the searportion 48 will move into engagement with the hammer shoulder 44 whenthe hammer is cocked. This engagement will occur regardless of theposition of the trigger 2 since the latter has been disconnected fromthe sear. When the bolt assembly 82 has returned to its batteryposition, the disconnector 26 will be free to slide forward to theposition shown in FIG. 2 under the influence of the spring 24 and theconnector 12. Thus the spring 24 serves to return the disconnector 26 toits original position, and serves to return the connector 12 intocontact with the sear portion 48. When the bolt assembly 82 has returnedto its battery position, the gun is again ready to fire.

FIGS. 6 and 7 illustrate the operation of the safety 64. When the safety64 is pushed to its on position, the connector projection 16 moves upthe camming surface 68 onto the exterior surface of the safety. Thedetent 70 moves into the second concavity 92 to hold the safety inplace. When the projection 16 moves onto the exterior surface of thesafety 64, the connector 12 is slid rearwardly over the pin 6 and intoabutment with the trigger housing 74 at 75, and the connector lip 14 ismoved out of engagement with the sear portion 48. Thus the trigger 2 isdisconnected from the sear 46 and cannot be used to fire the gun. As afurther safety feature, the exterior surface of the safety 64 moves intoa position immediately underlying the sear portion 48 so that the latteris locked into engagement with the hammer shoulder 44. Thus the safetyrenders the trigger inoperable to fire the gun, and also prevents thesear from being accidentally jarred free from the hammer. Since theconnector 12 is moved into abutment with the surface 75 on the triggerhousing 74 when the safety 64 is on, the trigger 2 cannot be pulled whenthe safety is on. The immobility of the trigger 2 when the safety 64 ison thus contributes to the feeling of safeness experienced by theshooter.

It is thus readily apparent that the mechanism of this inventionoperates as a unitary piece when the trigger is pulled to fire the gun,but operates as a plurality of individual units when the bolt assemblyis reciprocated. During reciprocation each unit is free to perform itsfunction independently of the other members of the mechanism. Thetrigger assembly positively precludes firing the gun by pulling thetrigger unless the bolt assembly is locked in its battery position. Thetrigger assembly of this invention also comprises a safety whichoperates to disconnect the trigger from the sear and to lock the searinto engagement with the hammer, thereby providing dual means forpreventing the weapon from being fired when the safety is on.

Since many changes and variations of the disclosed embodiment of theinvention may be made without departing from the inventive concept, itis not intended to limit the invention otherwise than as required by theappended claims.

We claim:

I. A mechanism for use with a semiautomatic firearm having areciprocating bolt assembly, said mechanism comprising:

a. hammer means;

b. sear means operative to engage said hammer means to retain the latterin a cocked position;

c. trigger means; d. connector means disposed in disconnectableengagement with said sear means;

e. spring means connected to said trigger means, said spring means beingoperative to bias said trigger means against said connector means toprovide constant engagement between said trigger means and saidconnector means, whereby said connector means is operable to immediatelytransfer motion of said trigger means to said sear means; and

disconnector means operable to contact said connector means and move thelatter out of engagement with said sear means when said firearm isfired.

2. The mechanism of claim 1, wherein said spring means is also connectedto said connector means to bias the latter into engagement with saidsear means and with said disconnector means.

3. The mechanism of claim 1, wherein said disconnector means includes aportion adjacent said bolt assembly to contact said bolt assembly whenthe latter-is moved out of its battery position, and to thereby movesaid disconnector means against said connector means.

4. The mechanism of claim I, further comprising adjustable resilientmeans contacting said sear means to bias the latter toward said hammermeans.

5. The mechanism of claim 4, further comprising locking means operativeto engage said adjustable means to lock the latter in a preset position.

6. The mechanism of claim 1, further comprising safety means operativeto earn said connector means out of engagement with said sear means.

7. The mechanism of claim 6, wherein said safety means is furtheroperative to contact said sear means and lock the latter into engagementwith said hammer means.

8. A trigger assembly for use with a semiautomatic firearm having areciprocating bolt assembly, said trigger comprising:

a. hammer means;

b. a trigger housing on said firearm;

c. trigger means mounted in said trigger housing, said trigger meansbeing connected to said hammer means to retain the latter in a cockedposition, and actuation of said trigger means being operative to releasesaid hammer means for movement from its cocked position; and

d. safety means mounted in said trigger housing, said safety means beingoperable to disconnect said trigger means from said hammer means,thereby rendering said trigger means ineffective to release said hammermeans from its cocked position.

9. A trigger assembly for use with a semiautomatic firearm having areciprocating bolt assembly, said trigger assembly comprising:

a. a trigger housing on said firearm;

b. hammer means movably mounted in said trigger housing;

c. sear means pivotally mounted in said trigger housing, said sear meansbeing movable into engagement with said hammer means to retain thelatter in a cocked position;

d. trigger means movably mounted in said trigger housing;

e. connector means slidably mounted in said trigger housing saidconnector means being slidable into engagement with said sear means;

f. spring means connected to said trigger means, said spring means beingoperative to bias said trigger means into constant engagement with saidconnector means, whereby actuation of said trigger means immediatelymoves said connector means against said sear means to disengage thelatter from said hammer means; and

g. disconnector means slidably mounted in said trigger housing, saiddisconnector being slidable against said connector to slide the latterout of engagement with said sear means thereby freeing said sear meansfor movement independent of said connector.

10. The trigger assembly of claim 9, wherein said spring means alsoengages said connector means to urge the latter against said sear means.

ll. A trigger assembly for use with a semiautomatic firearm having areceiver and a reciprocating bolt assembly mounted in the receiver, saidtrigger assembly comprising:

a. a trigger housing secured to said receiver;

b. hammer means mounted on said trigger housing;

c. sear means mounted on said trigger housing, said sear means beingoperable to lock said hammer means in a cocked position;

d. spring means contacting said sear means, said spring means beingoperative to bias said sear means against said hammer means with apredetermined force;

e. adjustment means mounted on said trigger housing and contacting saidspring means, said adjustment having a plurality of positions operativeto vary the bias of said spring means imposed on said sear means; and

f. means on said receiver operative to engage said adjustment means andlock the latter in a preset position thereby stabilizing said sear bias.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,577,827 Dated May 4, 1971 Inventor(s) William J. Billet and Edwin S.Vartanian It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

In Column 1, line 8, the word "more" should be deleted and --move--should be inserted.

In Column 3, line 6, the word "is" should be deleted and --inshould beinserted.

In Column 3, line 23, the word "is" should be deleted and --inshould beinserted.

Signed and sealed this ll th day of September 1971.

(s EAL) Attest:

,JR. ROBERT GOTTSCHALK Attestlng Officer Acting Commj ssioncr of PatentsFORM POJOSO (10'69) USCOMM-DC soars-ps9 h U 5 GOVERNMENT PQINYINU OFFICEI959 0'365381

1. A mechanism for use with a semiautomatic firearm having areciprocating bolt assembly, said mechanism comprising: a. hammer means;b. sear means operative to engage said hammer means to retain the latterin a cocked position; c. trigger means; d. connector means disposed indisconnectable engagement with said sear means; e. spring meansconnected to said trigger means, said spring means being operative tobias said trigger means against said connector means to provide constantengagement between said trigger means and said connector means, wherebysaid connector means is operable to immediately transfer motion of saidtrigger means to said sear means; and f. disconnector means operable tocontact said connector means and move the latter out of engagement withsaid sear means when said firearm is fired.
 2. The mechanism of claim 1,wherein said spring means is also connected to said connector means tobias the latter into engagement with said sear means and with saiddisconnector means.
 3. The mechanism of claim 1, wherein saiddisconnector means includes a portion adjacent said bolt assembly tocontact said bolt assembly when the latter is moved out of its batteryposition, and to thereby move said disconnector means against saidconnector means.
 4. The mechanism of claim 1, further comprisingadjustable resilient means contacting said sear means to bias the lattertoward said hammer means.
 5. The mechanism of claim 4, furthercomprising locking means operative to engage said adjustable means tolock the latter in a preset position.
 6. The mechanism of claim 1,further comprising safety means operative to cam said connector meansout of engageMent with said sear means.
 7. The mechanism of claim 6,wherein said safety means is further operative to contact said searmeans and lock the latter into engagement with said hammer means.
 8. Atrigger assembly for use with a semiautomatic firearm having areciprocating bolt assembly, said trigger comprising: a. hammer means;b. a trigger housing on said firearm; c. trigger means mounted in saidtrigger housing, said trigger means being connected to said hammer meansto retain the latter in a cocked position, and actuation of said triggermeans being operative to release said hammer means for movement from itscocked position; and d. safety means mounted in said trigger housing,said safety means being operable to disconnect said trigger means fromsaid hammer means, thereby rendering said trigger means ineffective torelease said hammer means from its cocked position.
 9. A triggerassembly for use with a semiautomatic firearm having a reciprocatingbolt assembly, said trigger assembly comprising: a. a trigger housing onsaid firearm; b. hammer means movably mounted in said trigger housing;c. sear means pivotally mounted in said trigger housing, said sear meansbeing movable into engagement with said hammer means to retain thelatter in a cocked position; d. trigger means movably mounted in saidtrigger housing; e. connector means slidably mounted in said triggerhousing said connector means being slidable into engagement with saidsear means; f. spring means connected to said trigger means, said springmeans being operative to bias said trigger means into constantengagement with said connector means, whereby actuation of said triggermeans immediately moves said connector means against said sear means todisengage the latter from said hammer means; and g. disconnector meansslidably mounted in said trigger housing, said disconnector beingslidable against said connector to slide the latter out of engagementwith said sear means thereby freeing said sear means for movementindependent of said connector.
 10. The trigger assembly of claim 9,wherein said spring means also engages said connector means to urge thelatter against said sear means.
 11. A trigger assembly for use with asemiautomatic firearm having a receiver and a reciprocating boltassembly mounted in the receiver, said trigger assembly comprising: a. atrigger housing secured to said receiver; b. hammer means mounted onsaid trigger housing; c. sear means mounted on said trigger housing,said sear means being operable to lock said hammer means in a cockedposition; d. spring means contacting said sear means, said spring meansbeing operative to bias said sear means against said hammer means with apredetermined force; e. adjustment means mounted on said trigger housingand contacting said spring means, said adjustment having a plurality ofpositions operative to vary the bias of said spring means imposed onsaid sear means; and f. means on said receiver operative to engage saidadjustment means and lock the latter in a preset position therebystabilizing said sear bias.